Fiber reinforced polymer composites have been increasingly used by various industries such as aerospace and automotive due to their high specific stiffness and strength, chemical resistance and thermo-mechanical properties. To achieve the best part quality and cost-efficient processing, online cure-monitoring is desirable. In the present work, the objective was to obtain a correlation between the results of the dielectric analysis (DEA) and several material properties such as degree of cure, glass transition temperature (Tg) and gel point of epoxy systems. Experiments were conducted on four different resin types, commonly used for industrial applications. Moreover, these findings were evaluated finally in the resin transfer molding (RTM) process. At first, modeling of the curing kinetics of the resins was done. The necessary parameters were studied via differential scanning calorimetry (DSC) to allow the prediction of the degree of cure and the development of the Tg during curing. A relation between Tg and conversion was established which was used for the construction of diffusion-dominated reaction kinetics in the later stage of curing enhancing the cure-prediction quality. Dielectric analysis was then conducted to study the curing of the epoxy resin systems. This technique allows in-mold monitoring of the crosslinking. The ion viscosity was used for correlation with the above mentioned material properties and good agreement could be found. To precisely determine the gel-point of epoxies, rheological experiments were conducted. The focus was the precise correlation of the gel point from rheological experiments with dielectric results. The results agreed well between within experimental error. Finally, the obtained results of two chosen systems were compared and verified during RTM processing. Successful flow front and cure monitoring were done with the dielectric analysis. Good agreement with theoretical cure prediction and rheological properties were observed.